Journal of Rawalpindi Medical College (JRMC); 2012;16(2):97-99 97 Original Article Assessment of Serum Leptin Level and Insulin Resistance in Obese Subjects Ahsan Kazmi*, Abdus Sattar**, Rizwan Hashim**, Mohammad Younus***. * Department of Pathology, Rawalpindi Medical College,Rawalpindi; ** Armed Forces Institute of Pathology, Rawalpindi; *** Department of Pathology, Benazir Bhutto Hospital, Rawalpindi Abstract Background: To determine the relationship between serum leptin and insulin resistance in obese Pakistani subjects. Methods: In this observational study fifty healthy obese and overweight subjects were selected by non- probability convenience sampling. Age, sex, height, weight and body mass index (BMI) of subjects were recorded. Fasting plasma glucose, serum leptin and insulin were measured. Fifty healthy non-obese subjects served as control group. Results: Serum leptin concentration was higher in obese subjects (52.8 ± 24.6 ng/ml), with p value 0.001 than in non-obese healthy controls (6.3 ± 3.1 ng/ml). Serum leptin level was found higher in women (64.4ng/ml) than in men (40.4ng/ml) only in obese group. Insulin resistance was higher in obese subjects (11.1 ± 5.1), with p value 0.001 than control group (0.9 ± 0.4). BMI strongly correlated with leptin concentration (r = 0.59 & p = 0.001) and insulin resistance (r = 0.372 & p = 0.001) in obese group. There was highly significant correlation between serum leptin concentration and insulin resistance (r = 0.451 & p = 0.001) in this group. In the control group, there was no correlation between serum leptin concentration and insulin resistance (r = 0.166 & p = 0.249). Conclusions: Serum leptin is positively correlated with insulin resistance in obese subjects. Serum leptin level and insulin resistance are higher in obese subjects. Key Words: Leptin, insulin resistance, body mass index, obesity. Introduction Obesity is one of the major problems which the developed countries are facing and now it has become an increasing threat for developing countries also. The affluent class of these countries is facing the same problem. It is well known that obesity is a risk factor for the development of insulin resistance. Insulin resistance is the condition in which normal amounts of insulin are inadequate to produce proportionate insulin response in fat, muscle and liver cells. 1,2 Leptin is a protein product of the obesity gene and involved in the regulation of energy intake and energy expenditure. Although few persons with extreme obesity are leptin deficient but most obese persons have hyper-leptinemia proportional to body fat and appear to be insulin resistant. The type of relationship between serum leptin and insulin resistance is not clear especially in obese subjects. Some studies have shown that insulin resistance is related with low levels of leptin in blood while other studies do not support it. 3 The triad of obesity,insulin resistance and leptin still needs exploration in our setup. The present study was aimed to address this issue. Patients and Methods This observational study was conducted at Armed Forces Institute of Pathology & Benazir Bhutto Shaheed Hospital, Rawalpindi, Pakistan, from 1.12.2008 to 30.5.2009.Fifty obese and overweight subjects were selected. Their age, height, weight and body mass index (BMI) were recorded. Serum leptin and insulin levels were measured in the fasting blood samples. Fifty healthy non-obese subjects were selected as control group. Weight of 23.1-27.4 kg/m 2 ,27.5-40 kg/m 2 and 18.5-23.0 kg/m 2 were considered as overweight, obese and non-obese, respectively. These BMI values were used under the “guidelines for Asian populations” issued in year 2000 by The International Association for the Study of Obesity and the International Obesity Task Force of World Health Organization, Western Pacific Region, Australia. 4 Height (cms) was measured using wall- mounted stadiometer and weight (kg) was determined using a weighing balance to calculate BMI (as an expression of obesity). BMI was calculated by the formula: BMI= Weight (kg)/ Height (m 2 ) After an overnight fast, blood samples were obtained in the morning between 0800-0900 hours for plasma glucose, insulin and leptin levels.Insulin resistance was calculated by Homeostasis Model